Concrete vessel



L. COKE-HILL.

CONCRETE VESSEL.

APPLICATION FILED SEPT. 19, 1918.

Patented May 4,1920. I

//7 l/enlvr Llonel Coke-Ill LIONEL COKE-HILL, or noNraEAL, QUEBEC,CANADA.

CONCRETE VESSEL.

Specification of Letters Patent.

Patented May 4., 1920.

Application filed. September 19, 1918. Serial No. 254,882.

To all whom it may concern:

Be it known that I, LIONEL COKE-HILL, a subject of the King of GreatBritain, residing at the city of Montreal, in the Province of Quebec andDominion of Canada, have invented certain new and useful Improvements inConcrete Vessels, of which the following is a full, clear, and exactdescription.

This invention relates to improvements in concrete vessels and theobject of the invention is to provide a construction in which theconcrete is so disposed that its greatest inherent strength is utilized.

A further object is to provide a concrete vessel so constructed that theamount of metal reinforcement required will be very much less than thatordinarily used.

A still further object is to provide a concrete vessel so constructedthat the interior molds are practically uniform throughout. Variousother objects and advantages will be apparent from the followingdescription.

It is well known that the strength of concrete when subjected totension, flection or torsion stresses is very little, as compared withits strength when subjected to compression stresses. In a concretevessel, as ordinarily contructed, the sides are substantially flat slabsbetween the frames and these fiat slabs are subjected by water pressureand wave actionto constantly varying flection stresses. In order to makethe structure sufficiently strong, a very large amount of metalreinforcement is required, owing to the limitations of weight imposed bythe nature of the structure. Apart from the difficult form work, thisgreat amount of reinforcement makes an ordinarily constructed concretevessel an extremely expensive proposition, as compared with a concretefactory or warehouse building of the same weight. A reduction in theamount of metal can be effected only by greatly increasing the amount ofconcrete and a point is soon reached where the increased dead weight ofthe hull encroaches so seriously on the cargo carrying capacity of thevessel that it becomes an unpractical structure. The tendency,therefore, is to use the thinnest possible concrete slab and supply therequisite strength with. reinforcement. This practice yields acomparatively flexible structure, so that the concrete is constantlysubjected to considerable flection or panting stresses, which it is notwell able to withstand, and the tendency to crack and disintegrate isvery great. These comparatively thin slabs also require support atfrequent intervals, so that the frames are spaced quite close together.

According to the present invention, the hull is constructed of a seriesof approximately semi-circular slabs or arches, the arches beingdisposed in the longitudinal direction of the vessel and extending fromthe sheer line through the keel to the opposite sheer line. Thisconstruction is such that the concrete is always in compression, andtherefore its ability to' withstand external pressure is developed tothe maximum. The edges or wings of the arches meet and form the usualframes within the vessel. Longi tudinal stiffening is imparted. by thekeel and a suitable number of"ke'elsons and stringers. The addition of aconcrete deck resting on posts extending to the keel or keelsonscompletes the hullproper. In order to reduce the resistance of the waterto the vessels motion, a smooth outer sheathing is connected to thearches at their crowns. This sheathing is apertured in suitable placesto admit water pressure to the convex surfaces of the arches forming thehull proper. It therefore follows that the outer sheathing has equalpressures on opposite sides thereof and has no water pressure to sustainexcept the wave action. This sheathing may be of any suitable material,either wood, metal or concrete. As the concrete of the hull proper is sodisposed as to be constantly in compression, it is clear that a minimumamount of metal reinforcement will be required. Obviously, the usualamount of longitudinal reinforcement will be necessary. Thisreinforcement is provided by the outer smooth concrete walls orequivalent internal longitudinal walls which with the deck and bottomform a truss, in the usual manner, which is sufliciently stiff to resisthogging or sagging when the hull is subjected to wave action. If cracksshould develop in the concrete of the arches, the fact that the concreteis in constant compression will cause the cracks to close up, whereasexactly the opposite condition prevails with a flat" slab in which theworking causes the cracks to grow.

In the drawings which illustrate the in vention;-

Figure 1 is a vertical longitudinal section of a vessel constructedaccording to this invention.

Fig. 4 is a half cross section on the line 44, Fig. 2.

Fig. 5 is a view similar to Fig. 3 showing a slight modification.

Fig. 6 is a cross section in the forward part of the vessel.

Fig. 7 is a cross section on the line 7-7, Fi 3.

ig. 8 is a cross section on the'line 8-8,

Fig. 3.

eferring more particularly to the drawings, 11 designates a plurality ofsemi-circular walls or arches which form the hull of a vessel and whichextend from sheer line to sheer line through the keel, the arches beingdisposed with their extremities fore and aft. The extremities of thearches meet and form internal projections or frames 12. Transversebulkheads 13 may be provided where desired, preferably extending betweenthe frames 12 and forming continuations thereof across the hull. Thekeel 14 and other longitudinal members 15, as well as the deck 16, givestrength to the vessel in the longitudinal direction, the deck beingsupported by any suitable number of posts 17 as well as by the frames.The inner or concave surface of each arch may be struck from a center18, while the outer or convex surface is struck from a center 19 nearerthe center line of the vessel, with the result that the wall thicknessof each arch increases from the crown toward the extremities, thusgiving greater strength Where the arches unite. A smooth surfaced outersheathing 20 is connected to the arches at their crowns, the outersurface of this sheathing being tangent to the convex surfaces of thearches. This outer sheathing or wall 20 may be of concrete or any othersuitable material, and is provided. with apertures 21, which admit waterinto the spaces 22 formed between itself and the arches. This admissionof the water to the spaces 22 equalizes the pressure on opposite sidesof the plain wall, so that it has very little more than its own weightto support except the stresses to which it is subjected as forming partof the longitudinal stiffening. At the same time, this admission ofwater into the spaces 22 brings the actual water pressure on the hullagainst the convex surfaces of the arches forming the hull proper, whichformation is better able to withstand the pressures than a flat wall, asis well known. Apertures 23 may be formed through the keel andlongitudinal members in the spaces 22, these apertures being restrictedeither by their size or by means of valves, so as to regulate the flowof water in the spaces from side to side of the vessel as it heels. Theapertures 21 through the wall 20 will also be sufficiently restricted toseriously retard the flow of water into or out of the spaces 22 as thevessel rolls, this restriction being due either to the size of theapertures or to the provision of valves.

In Fig. 5 a slight modification is shown which consists in terminatingthe corrugated portion of the hull a few feet below the water line andcarrying a lower deck 24 clear to the external shell so that the fullwidth between external sheathings is available for cargo and additionalbuoyancy. The frames in this portion which are subjected tocomparatively slight pressures are constructed in the usual way.

The arches may be duplicated within the vessel so as to form completecircular tanks, as shown at 26, Fig. 2. Such a construction will notonly form a vessel suitable for oil or grain cargoes, but will also forma vessel particularly well adapted to withstand internal pressures. If avessel is particularly designed for oil or grain carrying or the like,the entire hull may be formed of these circular tanks, so that greatstrength will be obtained and the buoyancy of the vessel will be verylittle affected by rupture of the bottom in or between any of the tanks.Various modifications may be made in the structure, such as theprovision of longitudinal bulkheads connecting the extremities of thearches or dividing the vessel into two or more compartments. It ispreferred to increase the depth of the frames. 12 from deck to bilge andto further increase them from bilge to keel'with a still further increase at the bilge to adequately stiffen the structure. This will beclearly seen in Figs. 6, 7 and 8. V

WVhen the vessel is launched,.water enters the spaces 22 through theapertures 21 and rises to the level, so that the pressure is equalizedon opposite sides of the wall. 20 and. the real pressure sustained bythe hull is exerted against the convex surfacesof the arches. Owing tothe formation, this arch structure of the same thickness as a flat wallwill withstand much greater pressures, as the concrete is entirely incompression. Obviously, a much thinner and lighter curved wall with muchless metal reinforcement will. withstand the same pressure as a heavierflat wall with more metal reinforcement. It follows, therefore, that avessel constructed according to this invention may be built, having thesame strength as a concrete vessel constructed in the ordinary mannerbut with the use of much less metal reinforcement.

When the vessel rolls if the side spaces 22 are connected either throughopenings or valves in the longitudinal keelsons or by other suitablemeans, the water in these side spaces will act automatically as anantirolling device thus replacing the specially constructed tanks atpresent used. By the addition of valves to apertures 21 the side spaces22 may be utilized for the reception of any liquid cargo desired whenthe valves are closed with exactly the same results as when sea water isadmitted to these spaces.

The radii from which the arches are struck are preferably uniformthroughout the vessel. Therefore, a single set of inside molds used overand over again will be all that is necessary to mold the entire innersurface of the vessel. In certain instances at bow and stern, specialmolds will be required for the spaces 22 but, for the most part, theouter surfaces of the arches may be made from the same mold. This willobviously reduce the cost of mold or form work to a minimum.

Having thus described my invention, what I claim is 1. A concrete vesselhaving the hull thereof corrugated, the corrugations extendingtransversely.

2. A structure according to claim 1, in which the corrugations areapproximately semi-circular and all arranged with their convex surfacesoutward.

3. A concrete vessel having the hull thereof formed of a plurality ofarches the spans of which are disposed longitudinally, each archextending from the sheer line on one side through the keel to the sheerline on the other side.

4. A device according to claim 3, in which the extremities of the archesunite to form internal frames for the hull.

5. A device according to claim 3, having longitudinal members spanningthe arches and stiffening the structure longitudinally.

6. In combination with a device according to claim 3, an outer smoothsheathing connected to the arches at their crowns.

7. A device according to claim 6, in which apertures are formed throughthe outer sheathing below water level to admit water between thesheathing and arches.

8. In combination with a device according to claim 5, a smooth outersheathing attached to the arches on their crowns having apertures belowwater line to admit water between sheathing and arches, saidlongitudinal members being apertured in the spaces between the archesand sheathing.

9. A device according to claim 8, in which the apertures of thesheathing and longitudinal members are sufiiciently restricted to delaywater in the spaces between the sheathing and arches in equalizing andin 12. A device according to claim 3, in

which the convex surfaces of the arches are struck from centers nearerthe longitudinal axis of the vessel than the concave surfaces wherebythe arches increase in thickness t0- ward their extremities.

13. A device according to claim 6, in which the outer surface of thesheathing is approximately tangent to the convex surfaces of the arches,whereby the sheathing and arches merge.

14. A concrete vessel having an outer smooth sheathing and transversecorrugated hull proper, whereby spaces are formed at intervals extendingfrom sheer line to sheer line through the keel.

15. A device according to claim 14 in which a deck is continued to theouter sheathing forming horizontal division walls in said spaces belowwater line, the corrugated structure terminating at said deck.

In witness whereof, I have hereunto set my hand.

LIONEL COKE-HILL.

